For example, PLTs 1 and 2 disclose machine tools which machine workpieces. In these machine tools, workpieces are attached to tables which are arranged on base frames. At the base frames, discharge holes for discharging chips of workpieces which drop down from the tables extend from the front to the back of the base frames. At the discharge holes, for example, conveyor belts are used to discharge the chips from the backs of the base frames to the outside. On the other hand, working fluid which drops downward from the table is stored inside the discharge holes or in storage tanks which are arranged at the rear of the machine tools.
Above the base frames, feed mechanisms which make lifters to which tools are attached move along guide rails in for example the vertical direction, that is, the Y-axis, are arranged. These feed mechanisms are provided with pairs of top-bottom feed screws which are arranged in parallel with each other, that is, ball screws, and pairs of feed motors which individually drive these ball screws to rotate. The ball screws have nuts which are fastened to the lifters screwed with them. As a result, rotation of the ball screws causes the lifters, that is, tools, to move along the Y-axis in the top-bottom direction.
PLT 1: Japanese Patent No. 4542001
PLT 2: Japanese Patent No. 3697697